[menu list] Pressing ArrowUp freezes the page when no item is focusable and focus is on another element in the list #49468

Steps to reproduce

Steps:

1. Render a MenuList where every MenuItem is disabled and another focusable element sits inside the list, for example a search field above a "No results" item:

<MenuList>
  <li>
    <input aria-label="search" />
  </li>
  <MenuItem disabled>No results</MenuItem>
</MenuList>

2. Click in the input.
3. Press ArrowUp.

I reproduced it on master with a test in MenuList.test.js (jsdom). The same code ships in @mui/utils 9.5.0 and 10.0.0-alpha.0.

Current behavior

The tab freezes. The test never finishes; I had to kill it after 120 seconds.

MenuList forwards the keydown to useRovingTabIndex. Focus is neither on the container nor on an item, and no item is focusable, so getCurrentActiveItemIndex returns -1. ArrowUp then calls getNextActiveItem(snapshot, -1, 'previous', ...). getNextIndex only treats index 0 as the start of the list for 'previous', so it returns -2, then -3, and so on. The while (nextIndex !== -1) loop never meets -1 or its start index again.

Expected behavior

ArrowUp does nothing (no item can take focus) and the page stays responsive. getNextActiveItem documents -1 as "start before the first item", which getNextIndex already handles for 'next'.

Context

A menu with a search field whose results are all disabled or replaced by a disabled "No results" item.

Your environment

Reproduced on mui/material-ui master (e9fabee) with Node 22, vitest + jsdom.
Code path is the same in @mui/utils 9.5.0 (useRovingTabIndex.js, getNextIndex).

Search keywords: menu list arrow up freeze infinite loop disabled useRovingTabIndex